diff --git a/src/calibre/gui2/tweak_book/templates.py b/src/calibre/gui2/tweak_book/templates.py
index ea5e3ef97d..22add677b4 100644
--- a/src/calibre/gui2/tweak_book/templates.py
+++ b/src/calibre/gui2/tweak_book/templates.py
@@ -27,7 +27,7 @@ DEFAULT_TEMPLATES = {
 
     'css':
 '''\
-@charset utf-8;
+@charset "utf-8";
 /* Styles for {TITLE} */
 %CURSOR%
 ''',